Another suspect, who is a juvenile, also turned himself in late Friday afternoon and is being charged with two counts of armed robbery in connection with the same two robberies, said Lieutenant Philip ­Harrington, a spokesman for the Police Department.

On Thursday, the first suspect was charged with the two robberies. That suspect, also a juvenile, turned himself in at Brookline Police headquarters, accompanied by his lawyer. Police have not identified the two juveniles who have been charged.

The arrests come after four armed robberies occurred on streets surrounding the university’s campus between Sept. 23 and Tuesday.

Most of the victims were Boston University students and the robberies have put the BU community on edge.

About 300 students attended a town hall meeting about the robberies Wednesday.

In each robbery, the suspects were described as two or three males in their late teens or early 20s. They had shown or pointed a gun at the victims.

Harrington credited the ­arrests to good police work, but said no further information would be released Friday .

Milton and the two juveniles have been charged in connection with a robbery on Sept. 25 in which three students reported being robbed at gunpoint at St. Paul and ­Egmont streets.

In that robbery, police said one of the three assailants pulled out a semiautomatic handgun, cocked the weapon, and placed it against the stomach of one of the students.

Milton and the juveniles have also been charged in a robbery in the vicinity of St. Paul and Thatcher streets on Oct. 5, shortly after 5 p.m. in which three people described as teenaged black males ­approached a recent BU graduate and one of the teens wielded a handgun.

The teens fled on foot ­toward Commonwealth Avenue after the robbery, according to police.

On Wednesday, BU offered a $10,000 reward for tips leading to arrest and conviction for the robberies.

Police said Milton and the juvenile who turned himself in Friday will be arraigned Oct. 15 in Brookline District Court.